r - 在R中选择一个带窗口的时间段；格式 "dd/mm/yyyy h:m:s"(Windows 7)

Question

我遇到以下问题。我想使用以下代码为每日数据选择特定时间段，例如这个:

window(Modellwind.zoo, start = as.Date("01/Jan/2001 12:00:00"), end = as.Date("4/Jan/2001 12:00:00"))

我收到以下错误消息:charToDate(x) 中出现错误: 字符串不是标准的明确格式

当我尝试使用 Anydate 函数找到可接受的时间格式时，它也不起作用:

library(anytime)
anydate("01/Jan/2001 12:00:00")

使用以下代码:

window(Modellwind.zoo, start = as.Date("2001-01-01"), end = as.Date("2001-01-04")) 

不幸的是，我收到以下错误:

 **Warning messages:
  1: In which(in.index & all.indexes >= start & all.indexes <= end) :
  Incompatible methods ("Ops.dates", "Ops.Date") for ">="
  2: In which(in.index & all.indexes >= start & all.indexes <= end) :
  Incompatible methods ("Ops.dates", "Ops.Date") for "<="**

以下代码包含 Modellwind.zoo 的示例。

structure(c(9.08093655399134, 6.51590181162631, 7.14637946155745, 
1.43900253813098, 6.78880326680026, 14.3182887821646, 16.3360242476697, 
16.1781018622214, 17.2200845065928, 15.6439142273171, 8.10504553259712, 
3.78898221928137, 6.78608582121557, 7.18116948778303, 5.0299974451978, 
3.49148782050232, 6.9941692218925, 8.45512766287497, 12.0693672354131, 
11.987955907515, 10.3290912344961, 13.4506307038479, 21.7989491163794, 
14.0085737502259, 14.5883127217965, 11.8048508250059, 24.7915690531695, 
19.151192329502, 12.1739793389357, 11.9410486288817, 20.9967608089789, 
15.2111025271479, 5.90129944159158, 2.42733488656831, 7.20743282263504, 
22.737089035552, 14.8219437253637, 14.0558804343021, 8.98137356225915, 
12.9592918632241, 18.4870237580719, 9.11790624009415, 2.27721679625411, 
2.61125956054424, 3.26998407545227, 5.35392572192135, 4.95193258824599, 
6.86224460928498, 9.06594694653957, 12.4505570716657, 12.740653858499, 
15.8771799446521, 12.5618618366812, 3.58848453998801, 10.9966305297934, 
4.86674413518877, 10.7031531327265, 16.2043681264107, 12.0587344974091, 
2.10949588086561), index = structure(c(18659.5, 18660.5, 18661.5, 
18662.5, 18663.5, 18664.5, 18665.5, 18666.5, 18667.5, 18668.5, 
18669.5, 18670.5, 18671.5, 18672.5, 18673.5, 18674.5, 18675.5, 
18676.5, 18677.5, 18678.5, 18679.5, 18680.5, 18681.5, 18682.5, 
18683.5, 18684.5, 18685.5, 18686.5, 18687.5, 18688.5, 18689.5, 
18690.5, 18691.5, 18692.5, 18693.5, 18694.5, 18695.5, 18696.5, 
18697.5, 18698.5, 18699.5, 18700.5, 18701.5, 18702.5, 18703.5, 
18704.5, 18705.5, 18706.5, 18707.5, 18708.5, 18709.5, 18710.5, 
18711.5, 18712.5, 18713.5, 18714.5, 18715.5, 18716.5, 18717.5, 
18718.5), .Dim = 60L, format = structure(c("dd/mm/yyyy", "h:m:s"
), .Names = c("dates", "times")), origin = c(12L, 1L, 1949L), class = c("chron", 
"dates", "times")), class = "zoo")

Answer 1

Modellwind.zoo的索引是chron。这就是为什么您尝试按 Date 进行子集化的尝试不成功(您的第一次尝试失败，因为 as.Date 需要 %Y-%m-%d 格式)。在按 Date 进行子集化之前，将索引更改为 Date:

Modellwind.zoo.Date <- Modellwind.zoo
index(Modellwind.zoo.Date) <- as.Date(index(Modellwind.zoo.Date))
window(Modellwind.zoo.Date, start = as.Date("2001-01-01"), end = as.Date("2001-01-04"))
# 2001-01-01 2001-01-02 2001-01-03 2001-01-04 
#   9.080937   6.515902   7.146379   1.43900

或者将索引保留为 chron 并按 chron 对象划分子集。请注意，Modellwind.zoo 中 chron 索引的原点是 1949-12-01，而不是默认的 chron 原点 1990-01-01，因此您需要指定它是为了避免有关来源不匹配的警告。

beg.chron <- as.chron("01/01/2001", origin = c(12, 1, 1949))
end.chron <- as.chron("01/04/2001", origin = c(12, 1, 1949))
window(Modellwind.zoo, start = beg.chron, end = end.chron)
# (01/Jan/2001 12:00:00) (02/Jan/2001 12:00:00) (03/Jan/2001 12:00:00) 
#               9.080937               6.515902               7.146379